1. Field of the Invention
The invention relates to a display device, and more particularly to a liquid crystal display device.
2. Description of the Related Art
Liquid crystal displays (LCD) have become widely used, with a working principle based on alignment alteration of liquid crystal molecules by application of an electrical field so as to change the path of light passing therethrough. Typically, an LCD includes two opposite substrates with a gap therebetween containing liquid crystal. Both substrates are formed with electrodes to control orientation and arrangement of liquid crystals. Images are displayed on the LCD panel by controlling orientation of liquid crystals with electrical field, in which bright dots or dark dots are generated where the light passes or is blocked.
FIG. 1 is a plan view of a conventional display panel 100. Referring to FIG. 1, an array substrate 102 comprising an array region 104 is provided.
A plurality of first signal lines 108 are disposed on the periphery of the array substrate 102. Most of the first signal lines 108 are parallel to the edge of the array substrate 102, providing signals or power to the driving circuits of the display panel 100.
The array substrate 102 and a second substrate 110 are sealed by a sealant 112 (the dot area in FIG. 1), disposed at the periphery of the array substrate 102 and the second substrate 110. Liquid crystals are injected into the space between the array substrate 102 and the second substrate 110. A plurality of driving ICs 114 are disposed on an extending area 116 of the array substrate 102 beyond the overlapping area of the second substrate 110 and the array substrate 102. A plurality of second signal lines 118 are arranged in a fan shape to supply signals or power from the driving ICs 114 to the driving circuits.
FIG. 2A is an enlarged view of region 101 in FIG. 1. FIG. 2B is a cross section along line I-I′ of FIG. 2A. Referring to FIG. 2A and FIG. 2B, a first dielectric layer 120 is formed on the array substrate 102. An interlayer dielectric layer 124 is formed on the first dielectric layer 120. The first signals lines 108 parallel to the edge of the array substrate 102 are metal lines, such as Mo, Al or combinations thereof or stacked layers thereof. Typically, in a low temperature polysilicon thin film transistor liquid crystal display device, a planarization layer 130 is formed on the metal line 108 and the interlayer dielectric layer 124. A sealant 112 is formed on the planarization layer 130 for sealing the second substrate 110.
FIG. 3A is an enlarged view of region 103 in FIG. 1. FIG. 3B is a cross section along line I-I′ of FIG. 3A. Referring to FIG. 3A and FIG. 3B, the second signals lines 118 supplying signals or power from the driving ICs 114 to the driving circuits are metal lines, such as Mo, Al or combinations thereof or stacked layers thereof. Typically, in a low temperature polysilicon thin film transistor liquid crystal display device, a planarization layer 130 is formed on the second signal lines 118 and the interlayer dielectric layer 124.
Adhesion between the metal lines 118 and 108 and the planarization layer 130 is worse than that between the interlayer dielectric layer 124 and the polarization layer 130. Consequently, peeling is likely to occur at the interface between the metal lines 118 or 108 and the planarization layer 130 when the display panel 100 is impacted. Thus, liquid crystals between the array substrate 116 and the second substrate 110 easily leak.